Cyanoacrylate adhesive compositions typically are regarded as having insufficient impact resistance and toughness, a shortcoming which is manifested by low peel strength. Various measures have been proposed to increase the peel strength of cyanoacrylate adhesives. Among such measures are the inclusion of an additive in such adhesives. One proposed additive is prepared by grafting styrene on a rubbery copolymer backbone (e.g., polybutadiene or a styrene-butadiene copolymer), shown in Japanese Published Patent No. 47-51807. Another proposed additive is selected from acrylonitrile-butadiene-styrene ("ABS") terpolymers, methacrylate-butadiene-styrene ("MBS") terpolymers, and vinylidene chloride-acrylonitrile ("VAC") copolymers, shown in U.S. Pat. No. 4,102,945. These latter additives are part of a class of materials which frequently are referred to as "core-shell" or "core-sheath" copolymers, and their chief use is not as an additive for cyanoacrylates, but rather as impact modifiers for polyvinyl chloride resins.